Mobile device and optical imaging lens thereof

ABSTRACT

Present embodiments provide for a mobile device and an optical imaging lens thereof. The optical imaging lens may comprise an aperture stop and four lens elements positioned sequentially from an object side to an image side. By controlling the convex or concave shape of the surfaces of the lens elements and designing parameters satisfying at least two inequalities, the optical imaging lens may exhibit better optical characteristics and the total length of the optical imaging lens may be shortened.

INCORPORATION BY REFERENCE

This application claims priority from R.O.C. Patent Application No.104117217, filed on May 28, 2015, the contents of which are herebyincorporated by reference in their entirety for all purposes.

TECHNICAL FIELD

The present disclosure relates to a mobile device and an optical imaginglens thereof, and particularly, relates to a mobile device applying anoptical imaging lens having four lens elements and an optical imaginglens thereof.

BACKGROUND

The ever-increasing demand for smaller sized mobile devices, such ascell phones, digital cameras, etc. has triggered a corresponding andgrowing need for smaller sized photography modules. Such modules maycomprise elements such as an optical imaging lens, a module housingunit, and an image sensor, etc., contained therein. Size reductions maybe contributed from various aspects of the mobile devices in light ofthe specification required in the market, such as good opticalcharacteristics, the difficulty to make each component, the nature ofthe material, the yield, and so on, therefore it is not as simple asjust proportionally shrinking the size of each component.

Therefore, it may be a challenge to develop optical imaging lens whichmay be capable to place with four lens elements therein, with a shorterlength, while also having good optical characteristics.

SUMMARY

Aspects of the present disclosure may provide a mobile device and anoptical imaging lens thereof. With controlling the convex or concaveshape of the surfaces and at least two inequalities, the length of theoptical imaging lens may be shortened while good optical characteristicsand system functionality may be maintained.

In an exemplary embodiment, an optical imaging lens may comprise,sequentially from an object side to an image side along an optical axis,an aperture stop, and first, second, third and fourth lens elements,each of the first, second, third and fourth lens elements may haverefracting index, an object-side surface facing toward the object sideand an image-side surface facing toward the image side and a centralthickness defined along the optical axis.

In the specification, parameters used here are: the distance between theaperture stop and the object-side surface of the next lens element alongthe optical axis, represented by TA (negative sign represents thedirection of the distance is from the image side to the object side),the central thickness of the first lens element, represented by T1, anair gap between the first lens element and the second lens element alongthe optical axis, represented by G12, the central thickness of thesecond lens element, represented by T2, an air gap between the secondlens element and the third lens element along the optical axis,represented by G23, the central thickness of the third lens element,represented by T3, an air gap between the third lens element and thefourth lens element along the optical axis, represented by G34, thecentral thickness of the fourth lens element, represented by T4, adistance between the image-side surface of the fifth lens element andthe object-side surface of a filtering unit along the optical axis,represented by G4F, the central thickness of the filtering unit alongthe optical axis, represented by TF, a distance between the image-sidesurface of the filtering unit and an image plane along the optical axis,represented by GFP, the central thickness of an image sensor along theoptical axis, represented by TI, a focusing length of the first lenselement, represented by f1, a focusing length of the second lenselement, represented by f2, a focusing length of the third lens element,represented by f3, a focusing length of the fourth lens element,represented by f4, the refracting index of the first lens element,represented by n1, the refracting index of the second lens element,represented by n2, the refracting index of the third lens element,represented by n3, the refracting index of the fourth lens element,represented by n4, the refracting index of the filtering unit,represented by n6, an abbe number of the first lens element, representedby v1, an abbe number of the second lens element, represented by v2, anabbe number of the third lens element, represented by v3, an abbe numberof the fourth lens element, represented by v4, an effective focal lengthof the optical imaging lens, represented by EFL or f, a distance betweenthe object-side surface of the first lens element and an image planealong the optical axis, represented by TTL, a sum of the centralthicknesses of all four lens elements, i.e. a sum of T1, T2, T3 and T4,represented by ALT, a sum of all three air gaps from the first lenselement to the fourth lens element along the optical axis, i.e. a sum ofG12, G23 and G34, represented by AAG, and a back focal length of theoptical imaging lens, which is defined as the distance from theimage-side surface of the fifth lens element to the image plane alongthe optical axis, i.e. a sum of G4F, TF and GFP, and represented by BFL.

In an aspect of the present disclosure, in the optical imaging lens, theobject-side surface of the first lens element may comprise a convexportion in a vicinity of a periphery of the first lens element, and theimage-side surface of the first lens element may comprise a convexportion in a vicinity of the periphery of the first lens element, thesecond lens element has negative refracting index, and the object-sidesurface of the second lens element may comprise a concave portion in avicinity of the optical axis and a concave portion in a vicinity of aperiphery of the second lens element, the third lens element haspositive refracting index, and the object-side surface of the third lenselement may comprise a concave portion in a vicinity of the optical axisand a concave portion in a vicinity of a periphery of the third lenselement, and the image-side surface thereof may comprise a convexportion in a vicinity of the periphery of the third lens element, theimage-side surface of the fourth lens element may comprise a concaveportion in a vicinity of the optical axis and a convex portion in avicinity of a periphery of the fourth lens element, the optical imaginglens may comprise no other lenses having refracting index beyond thefour lens elements, and the central thickness of the second lens elementis represented by T2, the central thickness of the fourth lens elementis represented by T4, an air gap between the third lens element and thefourth lens element along the optical axis is represented by G34, a sumof the central thicknesses of all four lens elements is represented byALT, and T2, T4, G34 and ALT satisfy the inequalities:

-   -   ALT/T2≦5.4 Inequality (1); and    -   (T2+T4)/G34≦4.0 Inequality (2).

In another exemplary embodiment, other inequality(s), such as thoserelating to the ratio among parameters could be taken intoconsideration. For example:

-   -   AAG/G12≦6.0 Inequality (3);    -   (G23+G34)/T4≦2.2 Inequality (4);    -   AAG/T4≦2.7 Inequality (5);    -   (T1+T2)/G12≦4.8 Inequality (6);    -   EFL/G23≧7.3 Inequality (7);    -   ALT/G12≦10.0 Inequality (8);    -   (T3+T4)/G12≦5.0 Inequality (9);    -   EFL/T1≧5.5 Inequality (10);    -   T1/G12≦2.9 Inequality (11);    -   ALT/G12≦9.2 Inequality (12);    -   EFL/(G23+G34)≧4.5 Inequality (13); and/or    -   EFL/(T1+T4)≧3.1 Inequality (14).

Aforesaid exemplary embodiments are not limited and could be selectivelyincorporated in other embodiments described herein.

In some exemplary embodiments, more details about the convex or concavesurface structure could be incorporated for one specific lens element orbroadly for plural lens elements to enhance the control for the systemperformance and/or resolution, for example, the image-side surface ofthe second lens element may comprise a convex portion in a vicinity ofthe optical axis and a concave portion in a vicinity of a periphery ofthe second lens element. It is noted that the details listed here couldbe incorporated in example embodiments if no inconsistency occurs.

In another exemplary embodiment, a mobile device comprising a housingand a photography module positioned in the housing may be provided. Thephotography module may comprise any of aforesaid example embodiments ofoptical imaging lens, a lens barrel, a module housing unit, a substrateand an image sensor. The lens barrel may be suitable for positioning theoptical imaging lens, the module housing unit may be suitable forpositioning the lens barrel, the substrate may be suitable forpositioning the module housing unit and the image sensor may bepositioned at the image side of the optical imaging lens.

By controlling the convex or concave shape of the surfaces and at leasetwo inequalities, the mobile device and the optical imaging lens thereofin exemplary embodiments may achieve good optical characteristics andmay effectively shorten the length of the optical imaging lens.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments will be more readily understood from the followingdetailed description when read in conjunction with the appended drawing,in which:

FIG. 1 is a cross-sectional view of one single lens element according tothe present disclosure;

FIG. 2 is a cross-sectional view showing the relation between the shapeof a portion and the position where a collimated ray meets the opticalaxis;

FIG. 3 is a cross-sectional view showing the relation between the shapeof a portion and he effective radius of a first example;

FIG. 4 is a cross-sectional view showing the relation between the shapeof a portion and he effective radius of a second example;

FIG. 5 is a cross-sectional view showing the relation between the shapeof a portion and he effective radius of a third example;

FIG. 6 is a cross-sectional view of a first embodiment of an opticalimaging lens having four lens elements according to the presentdisclosure;

FIG. 7 is a chart of longitudinal spherical aberration and other kindsof optical aberrations of a first embodiment of the optical imaging lensaccording to the present disclosure;

FIG. 8 is a table of optical data for each lens element of a firstembodiment of an optical imaging lens according to the presentdisclosure;

FIG. 9 is a table of aspherical data of a first embodiment of theoptical imaging lens according to the present disclosure;

FIG. 10 is a cross-sectional view of a second embodiment of an opticalimaging lens having four lens elements according to the presentdisclosure;

FIG. 11 is a chart of longitudinal spherical aberration and other kindsof optical aberrations of a second embodiment of the optical imaginglens according to the present disclosure;

FIG. 12 is a table of optical data for each lens element of the opticalimaging lens of a second embodiment of the present disclosure;

FIG. 13 is a table of aspherical data of a second embodiment of theoptical imaging lens according to the present disclosure;

FIG. 14 is a cross-sectional view of a third embodiment of an opticalimaging lens having four lens elements according to the presentdisclosure;

FIG. 15 is a chart of longitudinal spherical aberration and other kindsof optical aberrations of a third embodiment of the optical imaging lensaccording the present disclosure;

FIG. 16 is a table of optical data for each lens element of the opticalimaging lens of a third embodiment of the present disclosure;

FIG. 17 is a table of aspherical data of a third embodiment of theoptical imaging lens according to the present disclosure;

FIG. 18 is a cross-sectional view of a fourth embodiment of an opticalimaging lens having four lens elements according to the presentdisclosure;

FIG. 19 is a chart of longitudinal spherical aberration and other kindsof optical aberrations of a fourth embodiment of the optical imaginglens according the present disclosure;

FIG. 20 is a table of optical data for each lens element of the opticalimaging lens of a fourth embodiment of the present disclosure;

FIG. 21 is a table of aspherical data of a fourth embodiment of theoptical imaging lens according to the present disclosure;

FIG. 22 is a cross-sectional view of a fifth embodiment of an opticalimaging lens having four lens elements according to the presentdisclosure;

FIG. 23 is a chart of longitudinal spherical aberration and other kindsof optical aberrations of a fifth embodiment of the optical imaging lensaccording the present disclosure;

FIG. 24 is a table of optical data for each lens element of the opticalimaging lens of a fifth embodiment of the present disclosure;

FIG. 25 is a table of aspherical data of a fifth embodiment of theoptical imaging lens according to the present disclosure;

FIG. 26 is a cross-sectional view of a sixth embodiment of an opticalimaging lens having four lens elements according to the presentdisclosure;

FIG. 27 is a chart of longitudinal spherical aberration and other kindsof optical aberrations of a sixth embodiment of the optical imaging lensaccording the present disclosure;

FIG. 28 is a table of optical data for each lens element of the opticalimaging lens of a sixth embodiment of the present disclosure;

FIG. 29 is a table of aspherical data of a sixth embodiment of theoptical imaging lens according to the present disclosure;

FIG. 30 is a cross-sectional view of a seventh embodiment of an opticalimaging lens having four lens elements according to the presentdisclosure;

FIG. 31 is a chart of longitudinal spherical aberration and other kindsof optical aberrations of a seventh embodiment of the optical imaginglens according to the present disclosure;

FIG. 32 is a table of optical data for each lens element of a seventhembodiment of an optical imaging lens according to the presentdisclosure;

FIG. 33 is a table of aspherical data of a seventh embodiment of theoptical imaging lens according to the present disclosure;

FIG. 34 is a cross-sectional view of an eighth embodiment of an opticalimaging lens having four lens elements according to the presentdisclosure;

FIG. 35 is a chart of longitudinal spherical aberration and other kindsof optical aberrations of an eighth embodiment of the optical imaginglens according to the present disclosure;

FIG. 36 is a table of optical data for each lens element of the opticalimaging lens of an eighth embodiment of the present disclosure;

FIG. 37 is a table of aspherical data of an eighth embodiment of theoptical imaging lens according to the present disclosure;

FIG. 38 is a cross-sectional view of a ninth embodiment of an opticalimaging lens having four lens elements according to the presentdisclosure;

FIG. 39 is a chart of longitudinal spherical aberration and other kindsof optical aberrations of a ninth embodiment of the optical imaging lensaccording the present disclosure;

FIG. 40 is a table of optical data for each lens element of the opticalimaging lens of a ninth embodiment of the present disclosure;

FIG. 41 is a table of aspherical data of a ninth embodiment of theoptical imaging lens according to the present disclosure;

FIG. 42 is a cross-sectional view of a tenth embodiment of an opticalimaging lens having four lens elements according to the presentdisclosure;

FIG. 43 is a chart of longitudinal spherical aberration and other kindsof optical aberrations of a tenth embodiment of the optical imaging lensaccording the present disclosure;

FIG. 44 is a table of optical data for each lens element of the opticalimaging lens of a tenth embodiment of the present disclosure;

FIG. 45 is a table of aspherical data of a tenth embodiment of theoptical imaging lens according to the present disclosure;

FIG. 46 is a cross-sectional view of an eleventh embodiment of anoptical imaging lens having four lens elements according to the presentdisclosure;

FIG. 47 is a chart of longitudinal spherical aberration and other kindsof optical aberrations of an eleventh embodiment of the optical imaginglens according the present disclosure;

FIG. 48 is a table of optical data for each lens element of the opticalimaging lens of an eleventh embodiment of the present disclosure;

FIG. 49 is a table of aspherical data of an eleventh embodiment of theoptical imaging lens according to the present disclosure;

FIG. 50 is a table for the values of parameters of T1, T2, T3, T4, G12,G23, G34, AAG, ALT, EFL, BFL, ALT/T2, (T2+T4)/G34, AAG/G12,(G23+G34)/T4, AAG/T4, (T1+T2)/G12, EFL/G23, ALT/G12, (T3+T4)/G12,EFL/T1, T1/G12, ALT/G12, EFL/(G23+G34) and EFL/(T1+T4) of all elevenexample embodiments;

FIG. 51 is a structure of an example embodiment of a mobile device; and

FIG. 52 is a partially enlarged view of the structure of another exampleembodiment of a mobile device.

DETAILED DESCRIPTION

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following description taken inconjunction with the accompanying drawings, in which like referencenumbers indicate like features. Persons having ordinary skill in the artwill understand other varieties for implementing example embodiments,including those described herein. The drawings are not limited tospecific scale and similar reference numbers are used for representingsimilar elements. As used in the disclosures and the appended claims,the terms “example embodiment,” “exemplary embodiment,” and “presentembodiment” do not necessarily refer to a single embodiment, although itmay, and various example embodiments may be readily combined andinterchanged, without departing from the scope or spirit of the presentdisclosure. Furthermore, the terminology as used herein is for thepurpose of describing example embodiments only and is not intended to bea limitation of the disclosure. In this respect, as used herein, theterm “in” may include “in” and “on”, and the terms “a”, “an” and “the”may include singular and plural references. Furthermore, as used herein,the term “by” may also mean “from”, depending on the context.Furthermore, as used herein, the term “if” may also mean “when” or“upon”, depending on the context. Furthermore, as used herein, the words“and/or” may refer to and encompass any and all possible combinations ofone or more of the associated listed items.

In the present specification, the description “a lens element havingpositive refracting index (or negative refracting index)” may mean thatthe paraxial refracting index of the lens element in Gaussian optics ispositive (or negative). The description “An object-side (or image-side)surface of a lens element” may only include a specific region of thatsurface of the lens element where imaging rays are capable of passingthrough that region, namely the clear aperture of the surface. Theaforementioned imaging rays can be classified into two types, chief rayLc and marginal ray Lm. Taking a lens element depicted in FIG. 1 as anexample, the lens element may be rotationally symmetric, where theoptical axis I may be the axis of symmetry. The region A of the lenselement may be defined as “a portion in a vicinity of the optical axis”,and the region C of the lens element may be defined as “a portion in avicinity of a periphery of the lens element”. Besides, the lens elementmay also have an extending portion E extended radially and outwardlyfrom the region C, namely the portion outside of the clear aperture ofthe lens element. The extending portion E may be used for physicallyassembling the lens element into an optical imaging lens system. Undernormal circumstances, the imaging rays may not pass through theextending portion E because those imaging rays only pass through theclear aperture. The structures and shapes of the aforementionedextending portion E are only examples for technical explanation, thestructures and shapes of lens elements should not be limited to theseexamples. Note that the extending portions of the lens element surfacesdepicted in the following embodiments are partially omitted.

The following criteria are provided for determining the shapes and theportions of lens element surfaces set forth in the presentspecification. These criteria mainly determine the boundaries ofportions under various circumstances including the portion in a vicinityof the optical axis, the portion in a vicinity of a periphery of a lenselement surface, and other types of lens element surfaces such as thosehaving multiple portions.

FIG. 1 is a radial cross-sectional view of a lens element. Beforedetermining boundaries of those aforesaid portions, two referentialpoints may be defined first, central point and transition point. Thecentral point of a surface of a lens element may be a point ofintersection of that surface and the optical axis. The transition pointmay be a point on a surface of a lens element, where the tangent line ofthat point may be perpendicular to the optical axis. Additionally, ifmultiple transition points appear on one single surface, then thesetransition points may be sequentially named along the radial directionof the surface with numbers starting from the first transition point.For instance, the first transition point (closest one to the opticalaxis), the second transition point, and the Nth transition point(farthest one to the optical axis within the scope of the clear apertureof the surface). The portion of a surface of the lens element betweenthe central point and the first transition point may be defined as theportion in a vicinity of the optical axis. The portion located radiallyoutside of the Nth transition point (but still within the scope of theclear aperture) may be defined as the portion in a vicinity of aperiphery of the lens element. In some embodiments, there are otherportions existing between the portion in a vicinity of the optical axisand the portion in a vicinity of a periphery of the lens element; thenumbers of portions depend on the numbers of the transition point(s). Inaddition, the radius of the clear aperture (or a so-called effectiveradius) of a surface may be defined as the radial distance from theoptical axis I to a point of intersection of the marginal ray Lm and thesurface of the lens element.

Referring to FIG. 2, determining the shape of a portion is convex orconcave may depend on whether a collimated ray passing through thatportion converges or diverges. That is, while applying a collimated rayto a portion to be determined in terms of shape, the collimated raypassing through that portion may be bent and the ray itself or itsextension line may eventually meet the optical axis. The shape of thatportion may be determined by whether the ray or its extension line meets(intersects) the optical axis (focal point) at the object-side orimage-side. For instance, if the ray itself intersects the optical axisat the image side of the lens element after passing through a portion,i.e. the focal point of this ray is at the image side (see point R inFIG. 2), the portion may be determined as having a convex shape. On thecontrary, if the ray diverges after passing through a portion, theextension line of the ray intersects the optical axis at the object sideof the lens element, i.e. the focal point of the ray is at the objectside (see point M in FIG. 2), that portion may be determined as having aconcave shape. Therefore, referring to FIG. 2, the portion between thecentral point and the first transition point has a convex shape, theportion located radially outside of the first transition point has aconcave shape, and the first transition point is the point where theportion having a convex shape changes to the portion having a concaveshape, namely the border of two adjacent portions. Alternatively, thereis another way to determine whether a portion in a vicinity of theoptical axis has a convex or concave shape by referring to the sign ofan “R” value, which is the (paraxial) radius of curvature of a lenssurface. The R value may be used in optical design software such asZemax and CodeV. The R value usually appears in the lens data sheet inthe software. For an object-side surface, positive R may mean that theobject-side surface is convex, and negative R means that the object-sidesurface is concave. Conversely, for an image-side surface, positive Rmay mean that the image-side surface is concave, and negative R may meanthat the image-side surface is convex. The result found by using thismethod should be consistent as by using the other way mentioned above,which may determine surface shapes by referring to whether the focalpoint of a collimated ray is at the object side or the image side.

For none transition point cases, the portion in a vicinity of theoptical axis may be defined as the portion between 0-50% of theeffective radius (radius of the clear aperture) of the surface, whereasthe portion in a vicinity of a periphery of the lens element may bedefined as the portion between about 50% to about 100% of effectiveradius (radius of the clear aperture) of the surface.

Referring to the first example depicted in FIG. 3, only one transitionpoint, namely a first transition point, may appear within the clearaperture of the image-side surface of the lens element. Portion I may bea portion in a vicinity of the optical axis, and portion II may be aportion in a vicinity of a periphery of the lens element. The portion ina vicinity of the optical axis may be determined as having a concavesurface due to the R value at the image-side surface of the lens elementis positive. The shape of the portion in a vicinity of a periphery ofthe lens element may be different from that of the radially inneradjacent portion, i.e. the shape of the portion in a vicinity of aperiphery of the lens element may be different from the shape of theportion in a vicinity of the optical axis; the portion in a vicinity ofa periphery of the lens element may have a convex shape.

Referring to the second example depicted in FIG. 4, a first transitionpoint and a second transition point may exist on the object-side surface(within the clear aperture) of a lens element. In which portion I is theportion in a vicinity of the optical axis, and portion III is theportion in a vicinity of a periphery of the lens element. The portion ina vicinity of the optical axis has a convex shape because the R value atthe object-side surface of the lens element is positive. The portion ina vicinity of a periphery of the lens element (portion III) has a convexshape. What is more, there may be another portion having a concave shapeexisting between the first and second transition point (portion II).

Referring to a third example depicted in FIG. 5, no transition pointexists on the object-side surface of the lens element. In this case, theportion between about 0% to about 50% of the effective radius (radius ofthe clear aperture) may be determined as the portion in a vicinity ofthe optical axis, and the portion between about 50% to about 100% of theeffective radius may be determined as the portion in a vicinity of aperiphery of the lens element. The portion in a vicinity of the opticalaxis of the object-side surface of the lens element may be determined ashaving a convex shape due to its positive R value, and the portion in avicinity of a periphery of the lens element may be determined as havinga convex shape as well.

In the present disclosure, examples of an optical imaging lens which isa prime lens are provided. Example embodiments of an optical imaginglens may comprise an aperture stop, a first lens element, a second lenselement, a third lens element and a fourth lens element, each of thelens elements may comprise refracting index, an object-side surfacefacing toward an object side and an image-side surface facing toward animage side and a central thickness defined along the optical axis. Theselens elements may be arranged sequentially from the object side to theimage side along an optical axis, and example embodiments of the lensmay comprise no other lenses having refracting index beyond the fourlens elements. In an example embodiment: the object-side surface of thefirst lens element may comprise a convex portion in a vicinity of aperiphery of the first lens element, and the image-side surface of thefirst lens element may comprise a convex portion in a vicinity of theperiphery of the first lens element, the second lens element hasnegative refracting index, and the object-side surface of the secondlens element may comprise a concave portion in a vicinity of the opticalaxis and a concave portion in a vicinity of a periphery of the secondlens element, the third lens element has positive refracting index, andthe object-side surface of the third lens element may comprise a concaveportion in a vicinity of the optical axis and a concave portion in avicinity of a periphery of the third lens element, and the image-sidesurface thereof may comprise a convex portion in a vicinity of theperiphery of the third lens element, the image-side surface of thefourth lens element may comprise a concave portion in a vicinity of theoptical axis and a convex portion in a vicinity of a periphery of thefourth lens element, the optical imaging lens may comprise no otherlenses having refracting index beyond the four lens elements, and thecentral thickness of the second lens element is represented by T2, thecentral thickness of the fourth lens element is represented by T4, anair gap between the third lens element and the fourth lens element alongthe optical axis is represented by G34, a sum of the central thicknessesof all four lens elements is represented by ALT, and T2, T4, G34 and ALTsatisfy the inequalities:

-   -   ALT/T2≦5.4 Inequality (1); and    -   (T2+T4)/G34≦4.0 Inequality (2).

In some embodiments, the lens elements may be designed in light of theoptical characteristics and the length of the optical imaging lens. Forexample, the convex portion in a vicinity of a periphery of the firstlens element formed on the object-side surface thereof and the convexportion in a vicinity of a periphery of the first lens element formed onthe image-side surface thereof may assist in collecting light, thesecharacters along with the aperture stop positioned before theobject-side surface of the first lens element may assist in shorteningthe length of the optical imaging lens. Together with the negativerefracting index of the second lens element, the concave portion in avicinity of the optical axis and the concave portion in a vicinity of aperiphery of the second lens element formed on the object-side surfacethereof, the positive refracting index of the third lens element, theconcave portion in a vicinity of the optical axis and the concaveportion in a vicinity of a periphery of the third lens element formed onthe object-side surface thereof, the convex portion in a vicinity of aperiphery of the third lens element formed on the image-side surfacethereof, the concave portion in a vicinity of the optical axis and theconvex portion in a vicinity of a periphery of the fourth lens elementformed on the image-side surface thereof, the curvature of field anddistortion may be eliminated. Further, together with the convex portionin a vicinity of the optical axis and the convex portion in a vicinityof a periphery of the second lens element formed on the image-sidesurface thereof may assist in promoting the imaging quality.

To shorten the length of the optical imaging lens, the lens elements arerequired for a shorter thickness; however, considering both thedifficulty to assembly the optical imaging lens and imaging quality, theoptical imaging lens may be better configured if it satisfies aforesaidInequalities (1) and (2). Further, the optical imaging lens may bebetter configured if it satisfies aforesaid Inequalities (4), (6), (8),(9) and/or (11) to carry out great optical characters, short length, aswell as feasibility. Preferably, the value of ALT/T2 may be within3.8˜5.4, the value of (T2+T4)/G34 may be within 2.3˜4.0, the value of(G23+G34)/T4 may be within 1.2˜2.2, the value of (T1+T2)/G12 may bewithin 3.3˜4.8, the value of ALT/G12 may be within 7.0˜10.0 which may befurther less than 9.2 to assist in shortening the length of the opticalimaging lens, the value of (T3+T4)/G12 may be within 3.7˜5.0, and thevalue of T1/G12 may be within 1.7˜2.9.

To shorten the length of the optical imaging lens, the air gaps betweenthe lens elements are required for shorter distances, and the opticalimaging lens may be better configured if it satisfies: AAG/G12≦6.0 whichpreferably may be further within 2.8˜6.0, and/or AAG/T4≦2.7 whichpreferably may be further within 1.8˜2.7.

The length of the air gaps and the thickness of the lens elements may beshortened to achieve a short length of the optical imaging lens.However, considering the difficulty of assembling the lens elements andthe imaging quality, it may be helpful to satisfy at least one of thelimitations with respect to the ratio between a thickness of the lenselement, an air gap or a focusing length of the optical imaging lens asfollows to configure the optical imaging lens well: EFL/T1≧5.5,EFL/G23≧7.3, EFL/(G23+G34)≧4.5, and/or EFL/(T1+T4)≧3.1. Preferably, thevalue of EFL/T1 may be further within 5.5˜7.3, the value of EFL/G23 maybe further within 7.3˜10.5, the value of EFL/(G23+G34) may be furtherwithin 4.5˜6.0, and the value of EFL/(T1+T4) may be further within3.1˜4.2.

In light of the unpredictability in an optical system, in the presentdisclosure, satisfying these inequality listed above may preferablyshortening the length of the optical imaging lens, lowering thef-number, enlarging the shot angle, promoting the imaging quality and/orincreasing the yield in the assembly process.

When implementing example embodiments, more details about the convex orconcave surface could be incorporated for one specific lens element orbroadly for plural lens elements to enhance the control for the systemperformance and/or resolution, for example, the image-side surface ofthe second lens element may comprise a convex portion in a vicinity ofthe optical axis and a concave portion in a vicinity of a periphery ofthe second lens element. It is noted that the details listed here couldbe incorporated in example embodiments if no inconsistency occurs.

Several exemplary embodiments and associated optical data will now beprovided for illustrating example embodiments of optical imaging lenswith good optical characteristics and a shortened length. Reference isnow made to FIGS. 6-9. FIG. 6 illustrates an example cross-sectionalview of an optical imaging lens 1 having four lens elements of theoptical imaging lens according to a first example embodiment. FIG. 7shows example charts of longitudinal spherical aberration and otherkinds of optical aberrations of the optical imaging lens 1 according toan example embodiment. FIG. 8 illustrates an example table of opticaldata of each lens element of the optical imaging lens 1 according to anexample embodiment. FIG. 9 depicts an example table of aspherical dataof the optical imaging lens 1 according to an example embodiment.

As shown in FIG. 6, the optical imaging lens 1 of the present embodimentmay comprise, in order from an object side A1 to an image side A2 alongan optical axis, an aperture stop 100, a first lens element 110, asecond lens element 120, a third lens element 130 and a fourth lenselement 140. A filtering unit 150 and an image plane 160 of an imagesensor are positioned at the image side A2 of the optical lens 1. Eachof the first, second, third, fourth lens elements 110, 120, 130, 140 andthe filtering unit 150 may comprise an object-side surface111/121/131/141/151 facing toward the object side A1 and an image-sidesurface 112/122/132/142/152 facing toward the image side A2. The exampleembodiment of the filtering unit 150 illustrated may be an IR cut filter(infrared cut filter) positioned between the fourth lens element 140 andan image plane 160. The filtering unit 150 may selectively absorb lightwith specific wavelength from the light passing optical imaging lens 1.For example, IR light may be absorbed, and this will prohibit the IRlight which is not seen by human eyes from producing an image on theimage plane 160.

Please noted that during the normal operation of the optical imaginglens 1, the distance between any two adjacent lens elements of thefirst, second, third and fourth lens elements 110, 120, 130, 140 may bean unchanged value, i.e. the optical imaging lens 1 may be a prime lens.

Exemplary embodiments of each lens element of the optical imaging lens 1which may be constructed by plastic material will now be described withreference to the drawings.

An example embodiment of the first lens element 110 may have a positiverefracting index. The object-side surface 111 may be a convex surfacecomprising a convex portion 1111 in a vicinity of the optical axis and aconvex portion 1112 in a vicinity of a periphery of the first lenselement 110. The image-side surface 112 may comprise a concave portion1121 in a vicinity of the optical axis and a convex portion 1122 in avicinity of the periphery of the first lens element 110.

An example embodiment of the second lens element 120 may have negativerefracting index. The object-side surface 121 may be a concave surfacecomprising a concave portion 1211 in a vicinity of the optical axis anda concave portion 1212 in a vicinity of a periphery of the second lenselement 120. The image-side surface 122 may be a concave surfacecomprising a concave portion 1221 in a vicinity of the optical axis anda concave portion 1222 in a vicinity of the periphery of the second lenselement 120.

An example embodiment of the third lens element 130 has positiverefracting index. The object-side surface 131 may be a concave surfacecomprising a concave portion 1311 in a vicinity of the optical axis anda concave portion 1312 in a vicinity of a periphery of the third lenselement 130. The image-side surface 132 may be a convex surfacecomprising a convex portion 1321 in a vicinity of the optical axis and aconvex portion 1322 in a vicinity of the periphery of the third lenselement 130.

An example embodiment of the fourth lens element 140 may have negativerefracting index. The object-side surface 141 may comprise a convexportion 1411 in a vicinity of the optical axis and a concave portion1412 in a vicinity of a periphery of the fourth lens element 140. Theimage-side surface 142 may comprise a concave portion 1421 in a vicinityof the optical axis and a convex portion 1422 in a vicinity of theperiphery of the fourth lens element 140.

In example embodiments, air gaps may exist between the lens elements110, 120, 130, 140, the filtering unit 150 and the image plane 160 ofthe image sensor. For example, FIG. 1 illustrates the air gap d1existing between the first lens element 110 and the second lens element120, the air gap d2 existing between the second lens element 120 and thethird lens element 130, the air gap d3 existing between the third lenselement 130 and the fourth lens element 140, the air gap d4 existingbetween the fourth lens element 140 and the filtering unit 150 and theair gap d5 existing between the filtering unit 150 and the image plane160 of the image sensor. However, in other embodiments, any of theaforesaid air gaps may or may not exist. For example, the profiles ofopposite surfaces of any two adjacent lens elements may correspond toeach other, and in such situation, the air gap may not exist. The airgap d1 is denoted by G12, the air gap d2 is denoted by G23, the air gapd3 is denoted by G34 and the sum of d1, d2 and d3 is denoted by AAG.

FIG. 8 depicts the optical characteristics of each lens elements in theoptical imaging lens 1 of the present embodiment, and please refer toFIG. 50 for the values of T1, T2, T3, T4, G12, G23, G34, AAG, ALT, EFL,BFL, ALT/T2, (T2+T4)/G34, AAG/G12, (G23+G34)/T4, AAG/T4, (T1+T2)/G12,EFL/G23, ALT/G12, (T3+T4)/G12, EFL/T1, T1/G12, ALT/G12, EFL/(G23+G34)and EFL/(T1+T4) of the present embodiment.

The distance from the object-side surface 111 of the first lens element110 to the image plane 160 along the optical axis may be about 4.454 mm,and the image height may be about 2.94 mm.

The aspherical surfaces, including the object-side surface 111 and theimage-side surface 112 of the first lens element 110, the object-sidesurface 121 and the image-side surface 122 of the second lens element120, the object-side surface 131 and the image-side surface 132 of thethird lens element 130, the object-side surface 141 and the image-sidesurface 142 of the fourth lens element 140 are all defined by thefollowing aspherical formula:

${Z(Y)} = {{\frac{Y^{2}}{R}/\left( {1 + \sqrt{1 - {\left( {1 + K} \right)\frac{Y^{2}}{R^{2}}}}} \right)} + {\sum\limits_{i = 1}^{n}{a_{2\; i} \times Y^{2\; i}}}}$wherein, Y represents the perpendicular distance between the point ofthe aspherical surface and the optical axis; Z represents the depth ofthe aspherical surface (the perpendicular distance between the point ofthe aspherical surface at a distance Y from the optical axis and thetangent plane of the vertex on the optical axis of the asphericalsurface); R represents the radius of curvature of the surface of thelens element; K represents a conic constant; and a_(2i) represents anaspherical coefficient of 2i^(th) level. The values of each asphericalparameter are shown in FIG. 9.

Please refer to FIG. 7, part (a), longitudinal spherical aberration ofthe optical imaging lens in the present embodiment is shown in thecoordinate in which the horizontal axis represents focus and thevertical axis represents field of view, and FIG. 7, part (b),astigmatism aberration of the optical imaging lens in the presentembodiment in the sagittal direction is shown in the coordinate in whichthe horizontal axis represents focus and the vertical axis representsimage height, and FIG. 7, part (c), astigmatism aberration in thetangential direction of the optical imaging lens in the presentembodiment is shown in the coordinate in which the horizontal axisrepresents focus and the vertical axis represents image height, and FIG.7, part (d), distortion aberration of the optical imaging lens in thepresent embodiment is shown in the coordinate in which the horizontalaxis represents percentage and the vertical axis represents imageheight. The curves of different wavelengths (470 nm, 555 nm, 650 nm) areclosed to each other. This represents off-axis light with respect tothese wavelengths is focused around an image point. From the verticaldeviation of each curve shown therein, the offset of the off-axis lightrelative to the image point may be within about ±0.05 mm. Therefore, thepresent embodiment improves the longitudinal spherical aberration withrespect to different wavelengths. For astigmatism aberration in thesagittal direction, the focus variation with respect to the threewavelengths in the whole field may fall within about ±0.04 mm, forastigmatism aberration in the tangential direction, the focus variationwith respect to the three wavelengths in the whole field falls within±0.08 mm, and the variation of the distortion aberration may be withinabout ±2.5%.

Reference is now made to FIGS. 10-13. FIG. 10 illustrates an examplecross-sectional view of an optical imaging lens 2 having four lenselements of the optical imaging lens according to a second exampleembodiment. FIG. 11 shows example charts of longitudinal sphericalaberration and other kinds of optical aberrations of the optical imaginglens 2 according to the second example embodiment. FIG. 12 shows anexample table of optical data of each lens element of the opticalimaging lens 2 according to the second example embodiment. FIG. 13 showsan example table of aspherical data of the optical imaging lens 2according to the second example embodiment. The reference numberslabeled in the present embodiment are similar to those in the firstembodiment for the similar elements, but here the reference numbers areinitialed with 2, for example, reference number 231 for labeling theobject-side surface of the third lens element 230, reference number 232for labeling the image-side surface of the third lens element 230, etc.

As shown in FIG. 10, the optical imaging lens 2 of the presentembodiment, in an order from an object side A1 to an image side A2 alongan optical axis, may comprise an aperture stop 200, a first lens element210, a second lens element 220, a third lens element 230 and a fourthlens element 240.

The differences between the second embodiment and the first embodimentmay include the radius of curvature, thickness of each lens element, thedistance of each air gap, aspherical data, related optical parameters,such as back focal length, and the configuration of the concave/convexshape of the object-side surface 241, but the configuration of theconcave/convex shape of surfaces, comprising the object-side surfaces211, 221, 231 facing to the object side A1 and the image-side surfaces212, 222, 232, 242 facing to the image side A2, may be similar to thosein the first embodiment. Here and all the embodiments below, for clearlyshowing the drawings of the present embodiment, only the surface shapeswhich are different from that in the first embodiment are labeled.Specifically, for the configuration of the concave/convex shape of theobject-side surface 241, the difference between the present embodimentand the first embodiment may include a convex portion 2412 in a vicinityof a periphery of the fourth lens element 240 formed on the object-sidesurface 241 thereof. Please refer to FIG. 12 for the opticalcharacteristics of each lens elements in the optical imaging lens 2 ofthe present embodiment, and please refer to FIG. 50 for the values ofT1, T2, T3, T4, G12, G23, G34, AAG, ALT, EFL, BFL, ALT/T2, (T2+T4)/G34,AAG/G12, (G23+G34)/T4, AAG/T4, (T1+T2)/G12, EFL/G23, ALT/G12,(T3+T4)/G12, EFL/T1, T1/G12, ALT/G12, EFL/(G23+G34) and EFL/(T1+T4) ofthe present embodiment.

The distance from the object-side surface 211 of the first lens element210 to the image plane 260 along the optical axis may be about 4.327 mmand the image height may be about 2.94 mm.

As the longitudinal spherical aberration shown in FIG. 11, part (a), theoffset of the off-axis light relative to the image point may be withinabout ±0.05 mm. As the astigmatism aberration in the sagittal directionshown in FIG. 11, part (b), the focus variation with respect to thethree wavelengths in the whole field may fall within about ±0.04 mm. Asthe astigmatism aberration in the tangential direction shown in FIG. 11,part (c), the focus variation with respect to the three wavelengths inthe whole field may fall within about ±0.08 mm. As shown in FIG. 11,part (d), the variation of the distortion aberration may be within about±2.5%.

Compared with the first embodiment, the HFOV of the optical imaging lens2 may be greater than that in the first embodiment, and the length ofthe optical imaging lens 2 may be shorter.

Reference is now made to FIGS. 14-17. FIG. 14 illustrates an examplecross-sectional view of an optical imaging lens 3 having four lenselements of the optical imaging lens according to a third exampleembodiment. FIG. 15 shows example charts of longitudinal sphericalaberration and other kinds of optical aberrations of the optical imaginglens 3 according to the third example embodiment. FIG. 16 shows anexample table of optical data of each lens element of the opticalimaging lens 3 according to the third example embodiment. FIG. 17 showsan example table of aspherical data of the optical imaging lens 3according to the third example embodiment. The reference numbers labeledin the present embodiment are similar to those in the first embodimentfor the similar elements, but here the reference numbers are initialedwith 3, for example, reference number 331 for labeling the object-sidesurface of the third lens element 330, reference number 332 for labelingthe image-side surface of the third lens element 330, etc.

As shown in FIG. 14, the optical imaging lens 3 of the presentembodiment, in an order from an object side A1 to an image side A2 alongan optical axis, may comprise an aperture stop 300, a first lens element310, a second lens element 320, a third lens element 330 and a fourthlens element 340.

The differences between the third embodiment and the first embodimentmay include the radius of curvature and thickness of each lens element,the distance of each air gap, aspherical data and related opticalparameters, such as back focal length, and the configuration of theconcave/convex shape of the object-side surface 341, but theconfiguration of the concave/convex shape of surfaces, comprising theobject-side surfaces 311, 321, 331 facing to the object side A1 and theimage-side surfaces 312, 322, 332, 342 facing to the image side A2, maybe similar to those in the first embodiment. Specifically, for theconfiguration of the concave/convex shape of the object-side surface341, the difference between the present embodiment and the firstembodiment may include a convex portion 3412 in a vicinity of aperiphery of the fourth lens element 340 formed on the object-sidesurface 341 thereof. Please refer to FIG. 16 for the opticalcharacteristics of each lens elements in the optical imaging lens 3 ofthe present embodiment, and please refer to FIG. 50 for the values ofT1, T2, T3, T4, G12, G23, G34, AAG, ALT, EFL, BFL, ALT/T2, (T2+T4)/G34,AAG/G12, (G23+G34)/T4, AAG/T4, (T1+T2)/G12, EFL/G23, ALT/G12,(T3+T4)/G12, EFL/T1, T1/G12, ALT/G12, EFL/(G23+G34) and EFL/(T1+T4) ofthe present embodiment.

The distance from the object-side surface 311 of the first lens element310 to the image plane 360 along the optical axis may be about 4.408 mmand the image height may be about 2.94 mm.

As the longitudinal spherical aberration shown in FIG. 15, part (a), theoffset of the off-axis light relative to the image point may be withinabout ±0.05 mm. As the astigmatism aberration in the sagittal directionshown in FIG. 15, part (b), the focus variation with respect to thethree wavelengths in the whole field may fall within about ±0.08 mm. Asthe astigmatism aberration in the tangential direction shown in FIG. 15,part (c), the focus variation with respect to the three wavelengths inthe whole field may fall within about ±0.08 mm. As shown in FIG. 15,part (d), the variation of the distortion aberration may be within about±2.5%.

Compared with the first embodiment, the length of the optical imaginglens 3 may be shorter, and the distortion aberration of the opticalimaging lens 3 may be less.

Reference is now made to FIGS. 18-21. FIG. 18 illustrates an examplecross-sectional view of an optical imaging lens 4 having four lenselements of the optical imaging lens according to a fourth exampleembodiment. FIG. 19 shows example charts of longitudinal sphericalaberration and other kinds of optical aberrations of the optical imaginglens 4 according to the fourth embodiment. FIG. 20 shows an exampletable of optical data of each lens element of the optical imaging lens 4according to the fourth example embodiment. FIG. 21 shows an exampletable of aspherical data of the optical imaging lens 4 according to thefourth example embodiment. The reference numbers labeled in the presentembodiment are similar to those in the first embodiment for the similarelements, but here the reference numbers are initialed with 4, forexample, reference number 431 for labeling the object-side surface ofthe third lens element 430, reference number 432 for labeling theimage-side surface of the third lens element 430, etc.

As shown in FIG. 18, the optical imaging lens 4 of the presentembodiment, in an order from an object side A1 to an image side A2 alongan optical axis, may comprise an aperture stop 400, a first lens element410, a second lens element 420, a third lens element 430 and a fourthlens element 440.

The differences between the fourth embodiment and the first embodimentmay include the radius of curvature and thickness of each lens element,the distance of each air gap, aspherical data and related opticalparameters, such as back focal length, and the configuration of theconcave/convex shape of the object-side surface 441, but theconfiguration of the concave/convex shape of surfaces, comprising theobject-side surfaces 411, 421, 431 facing to the object side A1 and theimage-side surfaces 412, 422, 432, 442 facing to the image side A2, maybe similar to those in the first embodiment. Specifically, for theconfiguration of the concave/convex shape of the object-side surface441, the difference between the present embodiment and the firstembodiment may include a convex portion 4412 in a vicinity of aperiphery of the fourth lens element 440 formed on the object-sidesurface 441 thereof. Please refer to FIG. 20 for the opticalcharacteristics of each lens elements in the optical imaging lens 4 ofthe present embodiment, please refer to FIG. 50 for the values of T1,T2, T3, T4, G12, G23, G34, AAG, ALT, EFL, BFL, ALT/T2, (T2+T4)/G34,AAG/G12, (G23+G34)/T4, AAG/T4, (T1+T2)/G12, EFL/G23, ALT/G12,(T3+T4)/G12, EFL/T1, T1/G12, ALT/G12, EFL/(G23+G34) and EFL/(T1+T4) ofthe present embodiment.

The distance from the object-side surface 411 of the first lens element410 to the image plane 460 along the optical axis may be about 4.393 mmand the image height may be about 2.94 mm.

As the longitudinal spherical aberration shown in FIG. 19, part (a), theoffset of the off-axis light relative to the image point may be withinabout ±0.05 mm. As the astigmatism aberration in the sagittal directionshown in FIG. 19, part (b), the focus variation with respect to thethree wavelengths in the whole field may fall within about ±0.06 mm. Asthe astigmatism aberration in the tangential direction shown in FIG. 19,part (c), the focus variation with respect to the three wavelengths inthe whole field may fall within about ±0.08 mm. As shown in FIG. 19,part (d), the variation of the distortion aberration may be within about±2.5%.

Compared with the first embodiment, the length of the optical imaginglens 4 may be shorter, and the distortion aberration of the opticalimaging lens 4 may be less.

Reference is now made to FIGS. 22-25. FIG. 22 illustrates an examplecross-sectional view of an optical imaging lens 5 having four lenselements of the optical imaging lens according to a fifth exampleembodiment. FIG. 23 shows example charts of longitudinal sphericalaberration and other kinds of optical aberrations of the optical imaginglens 5 according to the fifth embodiment. FIG. 24 shows an example tableof optical data of each lens element of the optical imaging lens 5according to the fifth example embodiment. FIG. 25 shows an exampletable of aspherical data of the optical imaging lens 5 according to thefifth example embodiment. The reference numbers labeled in the presentembodiment are similar to those in the first embodiment for the similarelements, but here the reference numbers are initialed with 5, forexample, reference number 531 for labeling the object-side surface ofthe third lens element 530, reference number 532 for labeling theimage-side surface of the third lens element 530, etc.

As shown in FIG. 22, the optical imaging lens 5 of the presentembodiment, in an order from an object side A1 to an image side A2 alongan optical axis, may comprise an aperture stop 500, a first lens element510, a second lens element 520, a third lens element 530 and a fourthlens element 540.

The differences between the fifth embodiment and the first embodimentmay include the radius of curvature and thickness of each lens element,the distance of each air gap, aspherical data and related opticalparameters, such as back focal length, but the configuration of theconcave/convex shape of surfaces, comprising the object-side surfaces511, 521, 531, 541 facing to the object side A1 and the image-sidesurfaces 512, 522, 532, 542 facing to the image side A2, may be similarto those in the first embodiment. Please refer to FIG. 24 for theoptical characteristics of each lens elements in the optical imaginglens 5 of the present embodiment, please refer to FIG. 50 for the valuesof T1, T2, T3, T4, G12, G23, G34, AAG, ALT, EFL, BFL, ALT/T2,(T2+T4)/G34, AAG/G12, (G23+G34)/T4, AAG/T4, (T1+T2)/G12, EFL/G23,ALT/G12, (T3+T4)/G12, EFL/T1, T1/G12, ALT/G12, EFL/(G23+G34) andEFL/(T1+T4) of the present embodiment.

The distance from the object-side surface 511 of the first lens element510 to the image plane 560 along the optical axis may be about 4.402 mmand the image height may be about 2.94 mm.

As the longitudinal spherical aberration shown in FIG. 23, part (a), theoffset of the off-axis light relative to the image point may be withinabout ±0.05 mm. As the astigmatism aberration in the sagittal directionshown in FIG. 23, part (b), the focus variation with respect to thethree wavelengths in the whole field may fall within about ±0.04 mm. Asthe astigmatism aberration in the tangential direction shown in FIG. 23,part (c), the focus variation with respect to the three wavelengths inthe whole field may fall within about ±0.08 mm. As shown in FIG. 23,part (d), the variation of the distortion aberration may be within about±2.5%.

Compared with the first embodiment, the length of the optical imaginglens 5 may be shorter, the distortion aberration of the optical imaginglens 5 may be less, and the HFOV of the optical imaging lens 5 may begreater.

Reference is now made to FIGS. 26-29. FIG. 26 illustrates an examplecross-sectional view of an optical imaging lens 6 having four lenselements of the optical imaging lens according to a sixth exampleembodiment. FIG. 27 shows example charts of longitudinal sphericalaberration and other kinds of optical aberrations of the optical imaginglens 6 according to the sixth embodiment. FIG. 28 shows an example tableof optical data of each lens element of the optical imaging lens 6according to the sixth example embodiment. FIG. 29 shows an exampletable of aspherical data of the optical imaging lens 6 according to thesixth example embodiment. The reference numbers labeled in the presentembodiment are similar to those in the first embodiment for the similarelements, but here the reference numbers are initialed with 6, forexample, reference number 631 for labeling the object-side surface ofthe third lens element 630, reference number 632 for labeling theimage-side surface of the third lens element 630, etc.

As shown in FIG. 26, the optical imaging lens 6 of the presentembodiment, in an order from an object side A1 to an image side A2 alongan optical axis, may comprise an aperture stop 600, a first lens element610, a second lens element 620, a third lens element 630 and a fourthlens element 640.

The differences between the sixth embodiment and the first embodimentmay include the radius of curvature and thickness of each lens element,the distance of each air gap, aspherical data and related opticalparameters, such as back focal length, and the configuration of theconcave/convex shape of the object-side surface 641, but theconfiguration of the concave/convex shape of surfaces, comprising theobject-side surfaces 611, 621, 631 facing to the object side A1 and theimage-side surfaces 612, 622, 632, 642 facing to the image side A2, maybe similar to those in the first embodiment. Specifically, for theconfiguration of the concave/convex shape of the object-side surface641, the difference between the present embodiment and the firstembodiment may include a convex portion 6412 in a vicinity of aperiphery of the fourth lens element 640 formed on the object-sidesurface 641 thereof. Please refer to FIG. 28 for the opticalcharacteristics of each lens elements in the optical imaging lens 6 ofthe present embodiment, please refer to FIG. 50 for the values of T1,T2, T3, T4, G12, G23, G34, AAG, ALT, EFL, BFL, ALT/T2, (T2+T4)/G34,AAG/G12, (G23+G34)/T4, AAG/T4, (T1+T2)/G12, EFL/G23, ALT/G12,(T3+T4)/G12, EFL/T1, T1/G12, ALT/G12, EFL/(G23+G34) and EFL/(T1+T4) ofthe present embodiment.

The distance from the object-side surface 611 of the first lens element610 to the image plane 660 along the optical axis may be about 4.366 mmand the image height may be about 2.94 mm.

As the longitudinal spherical aberration shown in FIG. 27, part (a), theoffset of the off-axis light relative to the image point may be withinabout ±0.05 mm. As the astigmatism aberration in the sagittal directionshown in FIG. 27, part (b), the focus variation with respect to thethree wavelengths in the whole field may fall within about ±0.04 mm. Asthe astigmatism aberration in the tangential direction shown in FIG. 27,part (c), the focus variation with respect to the three wavelengths inthe whole field may fall within about ±0.08 mm. As shown in FIG. 27,part (d), the variation of the distortion aberration may be within about±2.5%.

Compared with the first embodiment, the length of the optical imaginglens 6 may be shorter and the HFOV of the optical imaging lens 6 may begreater.

Reference is now made to FIGS. 30-33. FIG. 30 illustrates an examplecross-sectional view of an optical imaging lens 7 having four lenselements of the optical imaging lens according to a seventh exampleembodiment. FIG. 31 shows example charts of longitudinal sphericalaberration and other kinds of optical aberrations of the optical imaginglens 7 according to the seventh embodiment. FIG. 32 shows an exampletable of optical data of each lens element of the optical imaging lens 7according to the seventh example embodiment. FIG. 33 shows an exampletable of aspherical data of the optical imaging lens 7 according to theseventh example embodiment. The reference numbers labeled in the presentembodiment are similar to those in the first embodiment for the similarelements, but here the reference numbers are initialed with 7, forexample, reference number 731 for labeling the object-side surface ofthe third lens element 730, reference number 732 for labeling theimage-side surface of the third lens element 730, etc.

As shown in FIG. 30, the optical imaging lens 7 of the presentembodiment, in an order from an object side A1 to an image side A2 alongan optical axis, may comprise an aperture stop 700, a first lens element710, a second lens element 720, a third lens element 730 and a fourthlens element 740.

The differences between the seventh embodiment and the first embodimentmay include the radius of curvature and thickness of each lens element,the distance of each air gap, aspherical data and related opticalparameters, such as back focal length, and the configuration of theconcave/convex shape of the object-side surface 741, but theconfiguration of the concave/convex shape of surfaces, comprising theobject-side surfaces 711, 721, 731 facing to the object side A1 and theimage-side surfaces 712, 722, 732, 742 facing to the image side A2, maybe similar to those in the first embodiment. Specifically, for theconfiguration of the concave/convex shape of the object-side surface741, the difference between the present embodiment and the firstembodiment may include a convex portion 7412 in a vicinity of aperiphery of the fourth lens element 740 formed on the object-sidesurface 741 thereof. Please refer to FIG. 32 for the opticalcharacteristics of each lens elements in the optical imaging lens 7 ofthe present embodiment, please refer to FIG. 50 for the values of T1,T2, T3, T4, G12, G23, G34, AAG, ALT, EFL, BFL, ALT/T2, (T2+T4)/G34,AAG/G12, (G23+G34)/T4, AAG/T4, (T1+T2)/G12, EFL/G23, ALT/G12,(T3+T4)/G12, EFL/T1, T1/G12, ALT/G12, EFL/(G23+G34) and EFL/(T1+T4) ofthe present embodiment.

The distance from the object-side surface 711 of the first lens element710 to the image plane 760 along the optical axis may be about 4.453 mmand the image height may be about 2.94 mm.

As the longitudinal spherical aberration shown in FIG. 31, part (a), theoffset of the off-axis light relative to the image point may be withinabout ±0.05 mm. As the astigmatism aberration in the sagittal directionshown in FIG. 31, part (b), the focus variation with respect to thethree wavelengths in the whole field may fall within about ±0.04 mm. Asthe astigmatism aberration in the tangential direction shown in FIG. 31,part (c), the focus variation with respect to the three wavelengths inthe whole field may fall within about ±0.08 mm. As shown in FIG. 31,part (d), the variation of the distortion aberration may be within about±2.5%.

Compared with the first embodiment, the length of the optical imaginglens 7 may be shorter.

Reference is now made to FIGS. 34-37. FIG. 34 illustrates an examplecross-sectional view of an optical imaging lens 8 having four lenselements of the optical imaging lens according to a eighth exampleembodiment. FIG. 35 shows example charts of longitudinal sphericalaberration and other kinds of optical aberrations of the optical imaginglens 8 according to the eighth embodiment. FIG. 36 shows an exampletable of optical data of each lens element of the optical imaging lens 8according to the eighth example embodiment. FIG. 37 shows an exampletable of aspherical data of the optical imaging lens 8 according to theeighth example embodiment. The reference numbers labeled in the presentembodiment are similar to those in the first embodiment for the similarelements, but here the reference numbers are initialed with 8, forexample, reference number 831 for labeling the object-side surface ofthe third lens element 830, reference number 832 for labeling theimage-side surface of the third lens element 830, etc.

As shown in FIG. 34, the optical imaging lens 8 of the presentembodiment, in an order from an object side A1 to an image side A2 alongan optical axis, may comprise an aperture stop 800, a first lens element810, a second lens element 820, a third lens element 830 and a fourthlens element 840.

The differences between the eighth embodiment and the first embodimentmay include the radius of curvature and thickness of each lens element,the distance of each air gap, aspherical data and related opticalparameters, such as back focal length, and the configuration of theconcave/convex shape of the object-side surface 841, but theconfiguration of the concave/convex shape of surfaces, comprising theobject-side surfaces 811, 821, 831 facing to the object side A1 and theimage-side surfaces 812, 822, 832, 842 facing to the image side A2, maybe similar to those in the first embodiment. Specifically, for theconfiguration of the concave/convex shape of the object-side surface841, the difference between the present embodiment and the firstembodiment may include a convex portion 8412 in a vicinity of aperiphery of the fourth lens element 840 formed on the object-sidesurface 841 thereof. Please refer to FIG. 36 for the opticalcharacteristics of each lens elements in the optical imaging lens 8 ofthe present embodiment, please refer to FIG. 50 for the values of T1,T2, T3, T4, G12, G23, G34, AAG, ALT, EFL, BFL, ALT/T2, (T2+T4)/G34,AAG/G12, (G23+G34)/T4, AAG/T4, (T1+T2)/G12, EFL/G23, ALT/G12,(T3+T4)/G12, EFL/T1, T1/G12, ALT/G12, EFL/(G23+G34) and EFL/(T1+T4) ofthe present embodiment.

The distance from the object-side surface 811 of the first lens element810 to the image plane 860 along the optical axis may be about 4.404 mmand the image height may be about 2.94 mm.

As the longitudinal spherical aberration shown in FIG. 35, part (a), theoffset of the off-axis light relative to the image point may be withinabout ±0.05 mm. As the astigmatism aberration in the sagittal directionshown in FIG. 35, part (b), the focus variation with respect to thethree wavelengths in the whole field may fall within about ±0.04 mm. Asthe astigmatism aberration in the tangential direction shown in FIG. 35,part (c), the focus variation with respect to the three wavelengths inthe whole field may fall within about ±0.08 mm. As shown in FIG. 35,part (d), the variation of the distortion aberration may be within about±2.5%.

Compared with the first embodiment, the length of the optical imaginglens 8 may be shorter, and the HFOV of the optical imaging lens 8 may begreater.

Reference is now made to FIGS. 38-41. FIG. 38 illustrates an examplecross-sectional view of an optical imaging lens 9 having four lenselements of the optical imaging lens according to a ninth exampleembodiment. FIG. 39 shows example charts of longitudinal sphericalaberration and other kinds of optical aberrations of the optical imaginglens 9 according to the ninth embodiment. FIG. 40 shows an example tableof optical data of each lens element of the optical imaging lens 9according to the ninth example embodiment. FIG. 41 shows an exampletable of aspherical data of the optical imaging lens 9 according to theninth example embodiment. The reference numbers labeled in the presentembodiment are similar to those in the first embodiment for the similarelements, but here the reference numbers are initialed with 9, forexample, reference number 931 for labeling the object-side surface ofthe third lens element 930, reference number 932 for labeling theimage-side surface of the third lens element 930, etc.

As shown in FIG. 38, the optical imaging lens 9 of the presentembodiment, in an order from an object side A1 to an image side A2 alongan optical axis, may comprise an aperture stop 900, a first lens element910, a second lens element 920, a third lens element 930 and a fourthlens element 940.

The differences between the ninth embodiment and the first embodimentmay include the radius of curvature and thickness of each lens element,the distance of each air gap, aspherical data and related opticalparameters, such as back focal length, and the configuration of theconcave/convex shape of the image-side surface 922, but theconfiguration of the concave/convex shape of surfaces, comprising theobject-side surfaces 911, 921, 931, 941 facing to the object side A1 andthe image-side surfaces 912, 932, 942 facing to the image side A2, maybe similar to those in the first embodiment. Specifically, for theconfiguration of the concave/convex shape of the image-side surface 922,the difference between the present embodiment and the first embodimentmay include a convex portion 9221 in a vicinity of the optical axisformed on the image-side surface 922 of the second lens element 920.Please refer to FIG. 40 for the optical characteristics of each lenselements in the optical imaging lens 9 of the present embodiment, pleaserefer to FIG. 50 for the values of T1, T2, T3, T4, G12, G23, G34, AAG,ALT, EFL, BFL, ALT/T2, (T2+T4)/G34, AAG/G12, (G23+G34)/T4, AAG/T4,(T1+T2)/G12, EFL/G23, ALT/G12, (T3+T4)/G12, EFL/T1, T1/G12, ALT/G12,EFL/(G23+G34) and EFL/(T1+T4) of the present embodiment.

The distance from the object-side surface 911 of the first lens element910 to the image plane 960 along the optical axis may be about 4.409 mmand the image height may be about 2.94 mm.

As the longitudinal spherical aberration shown in FIG. 39, part (a), theoffset of the off-axis light relative to the image point may be withinabout ±0.05 mm. As the astigmatism aberration in the sagittal directionshown in FIG. 39, part (b), the focus variation with respect to thethree wavelengths in the whole field may fall within about ±0.04 mm. Asthe astigmatism aberration in the tangential direction shown in FIG. 39,part (c), the focus variation with respect to the three wavelengths inthe whole field may fall within about ±0.08 mm. As shown in FIG. 39,part (d), the variation of the distortion aberration may be within about±2.5%.

Compared with the first embodiment, the length of the optical imaginglens 9 may be shorter, and the HFOV of the optical imaging lens 9 may begreater.

Reference is now made to FIGS. 42-45. FIG. 42 illustrates an examplecross-sectional view of an optical imaging lens 10 having four lenselements of the optical imaging lens according to a tenth exampleembodiment. FIG. 43 shows example charts of longitudinal sphericalaberration and other kinds of optical aberrations of the optical imaginglens 10 according to the tenth embodiment. FIG. 44 shows an exampletable of optical data of each lens element of the optical imaging lens10 according to the tenth example embodiment. FIG. 45 shows an exampletable of aspherical data of the optical imaging lens 10 according to thetenth example embodiment. The reference numbers labeled in the presentembodiment are similar to those in the first embodiment for the similarelements, but here the reference numbers are initialed with 10, forexample, reference number 1031 for labeling the object-side surface ofthe third lens element 1030, reference number 1032 for labeling theimage-side surface of the third lens element 1030, etc.

As shown in FIG. 42, the optical imaging lens 10 of the presentembodiment, in an order from an object side A1 to an image side A2 alongan optical axis, may comprise an aperture stop 1000, a first lenselement 1010, a second lens element 1020, a third lens element 1030 anda fourth lens element 1040.

The differences between the tenth embodiment and the first embodimentmay include the radius of curvature and thickness of each lens element,the distance of each air gap, aspherical data and related opticalparameters, such as back focal length, and the configuration of theconcave/convex shape of the object-side surface 1041 and the image-sidesurface 1022, but the configuration of the concave/convex shape ofsurfaces, comprising the object-side surfaces 1011, 1021, 1031 facing tothe object side A1 and the image-side surfaces 1012, 1032, 1042 facingto the image side A2, may be similar to those in the first embodiment.Specifically, for the configuration of the concave/convex shape of theimage-side surface 1022, the difference between the present embodimentand the first embodiment may include a convex portion 10221 in avicinity of the optical axis formed on the image-side surface 1022 ofthe second lens element 1020; for the configuration of theconcave/convex shape of the object-side surface 1041, the differencebetween the present embodiment and the first embodiment may include aconvex portion 10412 in a vicinity of a periphery of the fourth lenselement 1040 formed on the object-side surface 1041 thereof. Pleaserefer to FIG. 44 for the optical characteristics of each lens elementsin the optical imaging lens 10 of the present embodiment, please referto FIG. 50 for the values of T1, T2, T3, T4, G12, G23, G34, AAG, ALT,EFL, BFL, ALT/T2, (T2+T4)/G34, AAG/G12, (G23+G34)/T4, AAG/T4,(T1+T2)/G12, EFL/G23, ALT/G12, (T3+T4)/G12, EFL/T1, T1/G12, ALT/G12,EFL/(G23+G34) and EFL/(T1+T4) of the present embodiment.

The distance from the object-side surface 1011 of the first lens element1010 to the image plane 1060 along the optical axis may be about 4.404mm and the image height may be about 2.94 mm.

As the longitudinal spherical aberration shown in FIG. 43, part (a), theoffset of the off-axis light relative to the image point may be withinabout ±0.05 mm. As the astigmatism aberration in the sagittal directionshown in FIG. 43, part (b), the focus variation with respect to thethree wavelengths in the whole field may fall within about ±0.04 mm. Asthe astigmatism aberration in the tangential direction shown in FIG. 43,part (c), the focus variation with respect to the three wavelengths inthe whole field may fall within about ±0.08 mm. As shown in FIG. 43,part (d), the variation of the distortion aberration may be within about±2.5%.

Compared with the first embodiment, the length of the optical imaginglens 10 may be shorter, and the HFOV of the optical imaging lens 10 maybe greater.

Reference is now made to FIGS. 46-49. FIG. 46 illustrates an examplecross-sectional view of an optical imaging lens 11 having four lenselements of the optical imaging lens according to an eleventh exampleembodiment. FIG. 47 shows example charts of longitudinal sphericalaberration and other kinds of optical aberrations of the optical imaginglens 11 according to the eleventh embodiment. FIG. 48 shows an exampletable of optical data of each lens element of the optical imaging lens11 according to the eleventh example embodiment. FIG. 49 shows anexample table of aspherical data of the optical imaging lens 11according to the eleventh example embodiment. The reference numberslabeled in the present embodiment are similar to those in the firstembodiment for the similar elements, but here the reference numbers areinitialed with 11, for example, reference number 1131 for labeling theobject-side surface of the third lens element 1130, reference number1132 for labeling the image-side surface of the third lens element 1130,etc.

As shown in FIG. 46, the optical imaging lens 11 of the presentembodiment, in an order from an object side A1 to an image side A2 alongan optical axis, may comprise an aperture stop 1100, a first lenselement 1110, a second lens element 1120, a third lens element 1130 anda fourth lens element 1140.

The differences between the eleventh embodiment and the first embodimentmay include the radius of curvature and thickness of each lens element,the distance of each air gap, aspherical data and related opticalparameters, such as back focal length, and the configuration of theconcave/convex shape of the object-side surface 1141, but theconfiguration of the concave/convex shape of surfaces, comprising theobject-side surfaces 1111, 1121, 1131, 1141 facing to the object side A1and the image-side surfaces 1112, 1122, 1132, 1142 facing to the imageside A2, may be similar to those in the first embodiment. Specifically,for the configuration of the concave/convex shape of the object-sidesurface 1141, the difference between the present embodiment and thefirst embodiment may include a convex portion 11412 in a vicinity of aperiphery of the fourth lens element 1140 formed on the object-sidesurface 1141 thereof. Please refer to FIG. 48 for the opticalcharacteristics of each lens elements in the optical imaging lens 11 ofthe present embodiment, please refer to FIG. 50 for the values of T1,T2, T3, T4, G12, G23, G34, AAG, ALT, EFL, BFL, ALT/T2, (T2+T4)/G34,AAG/G12, (G23+G34)/T4, AAG/T4, (T1+T2)/G12, EFL/G23, ALT/G12,(T3+T4)/G12, EFL/T1, T1/G12, ALT/G12, EFL/(G23+G34) and EFL/(T1+T4) ofthe present embodiment.

The distance from the object-side surface 1111 of the first lens element1110 to the image plane 1160 along the optical axis may be about 4.459mm and the image height may be about 2.94 mm.

As the longitudinal spherical aberration shown in FIG. 47, part (a), theoffset of the off-axis light relative to the image point may be withinabout ±0.05 mm. As the astigmatism aberration in the sagittal directionshown in FIG. 47, part (b), the focus variation with respect to thethree wavelengths in the whole field may fall within about ±0.04 mm. Asthe astigmatism aberration in the tangential direction shown in FIG. 47,part (c), the focus variation with respect to the three wavelengths inthe whole field may fall within about ±0.08 mm. As shown in FIG. 47,part (d), the variation of the distortion aberration may be within about±2.5%.

Compared with the first embodiment, the optical imaging lens 11 may beeasier to make, and the HFOV of the optical imaging lens 11 may begreater.

Please refer to FIG. 50, which shows the values of parameters of alleleven embodiments.

Reference is now made to FIG. 51, which illustrates an examplestructural view of a first embodiment of mobile device 20 applying anaforesaid optical imaging lens. The mobile device 20 may comprise ahousing 21 and a photography module 22 positioned in the housing 21.Examples of the mobile device 20 may be, but are not limited to, amobile phone, a camera, a tablet computer, a personal digital assistant(PDA), etc.

As shown in FIG. 51, the photography module 22 may comprise an aforesaidoptical imaging lens with four lens elements, which may be a prime lensand for example the optical imaging lens 1 of the first embodiment, alens barrel 23 for positioning the optical imaging lens 1, a modulehousing unit 24 may suitable for positioning the lens barrel 23, asubstrate 162 for positioning the module housing unit 24, and an imagesensor 161 which may be positioned on the substrate 162 and at an imageside of the optical imaging lens 1. The image plane 160 may be formed onthe image sensor 161.

In some other example embodiments, the structure of the filtering unit150 may be omitted. In some example embodiments, the housing 21, thelens barrel 23, and/or the module housing unit 24 may be integrated intoa single component or assembled by multiple components. In some exampleembodiments, the image sensor 161 used in the present embodiment isdirectly attached to a substrate 162 in the form of a chip on board(COB) package, and such package is different from traditional chip scalepackages (CSP) since COB package does not require a cover glass beforethe image sensor 161 in the optical imaging lens 1. Aforesaid exemplaryembodiments are not limited to this package type and could beselectively incorporated in other described embodiments.

The four lens elements 110, 120, 130, 140 are positioned in the lensbarrel 23 in the way of separated by an air gap between any two adjacentlens elements.

The module housing unit 24 may comprise a lens backseat 2401 forpositioning the lens barrel 23 and an image sensor base 2406 positionedbetween the lens backseat 2401 and the image sensor 161. The lens barrel23 and the lens backseat 2401 are positioned along a same axis I-I′, andthe lens backseat 2401 is close to the outside of the lens barrel 23.The image sensor base 2406 is exemplarily close to the lens backseat2401 here. The image sensor base 2406 could be optionally omitted insome other embodiments of the present disclosure.

Because the length of the optical imaging lens 1 may be merely about4.454 mm, the size of the mobile device 20 may be quite small.Therefore, the embodiments described herein meet the market demand forsmaller sized product designs.

Reference is now made to FIG. 52, which shows another structural view ofa second embodiment of mobile device 20′ applying the aforesaid opticalimaging lens 1. One difference between the mobile device 20′ and themobile device 20 may be the lens backseat 2401 comprising a first seatunit 2402, a second seat unit 2403, a coil 2404 and a magnetic unit2405. The first seat unit 2402 is close to the outside of the lensbarrel 23, and positioned along an axis I-I′, and the second seat unit2403 is around the outside of the first seat unit 2402 and positionedalong with the axis I-I′. The coil 2404 may be positioned between thefirst seat unit 2402 and the inside of the second seat unit 2403. Themagnetic unit 2405 may be positioned between the outside of the coil2404 and the inside of the second seat unit 2403.

The lens barrel 23 and the optical imaging lens 1 positioned therein aredriven by the first seat unit 2402 for moving along the axis I-I′. Therest structure of the mobile device 20′ may be similar to the mobiledevice 20.

Similarly, because the length of the optical imaging lens 1, 4.454 mm,may be shortened, the mobile device 20′ may be designed with a smallersize and meanwhile good optical performance may still provided.Therefore, the present embodiment meets the demand of small sizedproduct design and the request of the market.

According to above illustration, the longitudinal spherical aberration,astigmatism aberration both in the sagittal direction and tangentialdirection and distortion aberration in all embodiments are meet userterm of a related product in the market. The off-axis light with respectto three different wavelengths (470 nm, 555 nm, 650 nm) is focusedaround an image point and the offset of the off-axis light relative tothe image point is well controlled with suppression for the longitudinalspherical aberration, astigmatism aberration both in the sagittaldirection and tangential direction and distortion aberration. The curvesof different wavelengths are closed to each other, and this representsthat the focusing for light having different wavelengths is good tosuppress chromatic dispersion. In summary, lens elements are designedand matched for achieving good imaging quality.

While various embodiments in accordance with the disclosed principlesbeen described above, it should be understood that they are presented byway of example only, and are not limiting. Thus, the breadth and scopeof exemplary embodiment(s) should not be limited by any of theabove-described embodiments, but should be defined only in accordancewith the claims and their equivalents issuing from this disclosure.Furthermore, the above advantages and features are provided in describedembodiments, but shall not limit the application of such issued claimsto processes and structures accomplishing any or all of the aboveadvantages.

Additionally, the section headings herein are provided for consistencywith the suggestions under 37 C.F.R. 1.77 or otherwise to provideorganizational cues. These headings shall not limit or characterize theinvention(s) set out in any claims that may issue from this disclosure.Specifically, a description of a technology in the “Background” is notto be construed as an admission that technology is prior art to anyinvention(s) in this disclosure. Furthermore, any reference in thisdisclosure to “invention” in the singular should not be used to arguethat there is only a single point of novelty in this disclosure.Multiple inventions may be set forth according to the limitations of themultiple claims issuing from this disclosure, and such claimsaccordingly define the invention(s), and their equivalents, that areprotected thereby. In all instances, the scope of such claims shall beconsidered on their own merits in light of this disclosure, but shouldnot be constrained by the headings herein.

What is claimed is:
 1. An optical imaging lens, sequentially from anobject side to an image side along an optical axis, comprising anaperture stop, and first, second, third and fourth lens elements, eachof said first, second, third and fourth lens elements having refractingindex, an object-side surface facing toward the object side and animage-side surface facing toward the image side and a central thicknessdefined along the optical axis, wherein: said object-side surface ofsaid first lens element comprises a convex portion in a vicinity of aperiphery of the first lens element, and said image-side surface of saidfirst lens element comprises a convex portion in a vicinity of theperiphery of the first lens element; said second lens element hasnegative refracting index, and said object-side surface of said secondlens element comprises a concave portion in a vicinity of the opticalaxis and a concave portion in a vicinity of a periphery of the secondlens element; said third lens element has positive refracting index, andsaid object-side surface of said third lens element comprises a concaveportion in a vicinity of the optical axis and a concave portion in avicinity of a periphery of the third lens element, and said image-sidesurface thereof comprises a convex portion in a vicinity of theperiphery of the third lens element; said image-side surface of saidfourth lens element comprises a concave portion in a vicinity of theoptical axis and a convex portion in a vicinity of a periphery of thefourth lens element; the optical imaging lens comprises no other lenseshaving refracting index beyond the four lens elements; and the centralthickness of the second lens element is represented by T2, the centralthickness of the fourth lens element is represented by T4, an air gapbetween the third lens element and the fourth lens element along theoptical axis is represented by G34, a sum of the central thicknesses ofall four lens elements is represented by ALT, and T2, T4, G34 and ALTsatisfy the inequalities: ALT/T2≦5.4; and (T2+T4)/G34≦4.0.
 2. Theoptical imaging lens according to claim 1, wherein an air gap betweenthe first lens element and the second lens element along the opticalaxis is represented by G12, a sum of all four air gaps from the firstlens element to the fourth lens element along the optical axis isrepresented by AAG, and G12 and AAG satisfy the inequality: AAG/G12≦6.0.3. The optical imaging lens according to claim 2, wherein the centralthickness of the first lens element is represented by T1, an effectivefocal length of the optical imaging lens is represented by EFL, and T1and EFL satisfy the inequality: EFL/T1≧5.5.
 4. The optical imaging lensaccording to claim 1, wherein an air gap between the second lens elementand the third lens element along the optical axis is represented by G23,and T4, G23 and G34 satisfy the inequality: (G23+G34)/T4≦2.2.
 5. Theoptical imaging lens according to claim 4, wherein the central thicknessof the first lens element is represented by T1, an air gap between thefirst lens element and the second lens element along the optical axis isrepresented by G12, and T1 and G12 satisfy the inequality: T1/G12≦2.9.6. The optical imaging lens according to claim 1, wherein a sum of allfour air gaps from the first lens element to the fourth lens elementalong the optical axis is represented by AAG, and T4 and AAG satisfy theinequality: AAG/T4≦2.7.
 7. The optical imaging lens according to claim6, wherein an air gap between the first lens element and the second lenselement along the optical axis is represented by G12, and G12 and ALTsatisfy the inequality: ALT/G12≦9.2.
 8. The optical imaging lensaccording to claim 1, wherein the central thickness of the first lenselement is represented by T1, an air gap between the first lens elementand the second lens element along the optical axis is represented byG12, and T1, T2 and G12 satisfy the inequality: (T1+T2)/G12≦4.8.
 9. Theoptical imaging lens according to claim 1, wherein an air gap betweenthe second lens element and the third lens element along the opticalaxis is represented by G23, an effective focal length of the opticalimaging lens is represented by EFL, and G23 and EFL satisfy theinequality: EFL/G23≧7.3.
 10. The optical imaging lens according to claim9, further comprising: said image-side surface of said second lenselement comprises a convex portion in a vicinity of the optical axis anda concave portion in a vicinity of a periphery of the second lenselement.
 11. The optical imaging lens according to claim 1, wherein anair gap between the first lens element and the second lens element alongthe optical axis is represented by G12, and G12 and ALT satisfy theinequality: ALT/G12≦10.0.
 12. The optical imaging lens according toclaim 11, wherein an air gap between the second lens element and thethird lens element along the optical axis is represented by G23, aneffective focal length of the optical imaging lens is represented byEFL, and G23, G34 and EFL satisfy the inequality: EFL/(G23+G34)≧4.5. 13.The optical imaging lens according to claim 1, wherein the centralthickness of the third lens element is represented by T3, an air gapbetween the first lens element and the second lens element along theoptical axis is represented by G12, and T3, T4 and G12 satisfy theinequality: (T3+T4)/G12≦5.0.
 14. The optical imaging lens according toclaim 13, wherein the central thickness of the first lens element isrepresented by T1, an effective focal length of the optical imaging lensis represented by EFL, and T1, T4 and EFL satisfy the inequality:EFL/(T1+T4)≧3.1.
 15. A mobile device, comprising: a housing; and aphotography module positioned in the housing and comprising: an opticalimaging lens, sequentially from an object side to an image side along anoptical axis, comprising an aperture stop, first, second, third andfourth lens elements, each of said first, second, third and fourth lenselements having refracting index, an object-side surface facing towardthe object side and an image-side surface facing toward the image sideand a central thickness defined along the optical axis, wherein: saidobject-side surface of said first lens element comprises a convexportion in a vicinity of a periphery of the first lens element, and saidimage-side surface of said first lens element comprises a convex portionin a vicinity of the periphery of the first lens element; said secondlens element has negative refracting index, and said object-side surfaceof said second lens element comprises a concave portion in a vicinity ofthe optical axis and a concave portion in a vicinity of a periphery ofthe second lens element; said third lens element has positive refractingindex, and said object-side surface of said third lens element comprisesa concave portion in a vicinity of the optical axis and a concaveportion in a vicinity of a periphery of the third lens element, and saidimage-side surface thereof comprises a convex portion in a vicinity ofthe periphery of the third lens element; said image-side surface of saidfourth lens element comprises a concave portion in a vicinity of theoptical axis and a convex portion in a vicinity of a periphery of thefourth lens element; the optical imaging lens comprises no other lenseshaving refracting index beyond the four lens elements; and the centralthickness of the second lens element is represented by T2, the centralthickness of the fourth lens element is represented by T4, an air gapbetween the third lens element and the fourth lens element along theoptical axis is represented by G34, a sum of the central thicknesses ofall four lens elements is represented by ALT, and T2, T4, G34 and ALTsatisfy the inequalities: ALT/T2≦5.4; and (T2+T4)/G34≦4.0; a lens barrelfor positioning the optical imaging lens; a module housing unit forpositioning the lens barrel; a substrate for positioning the modulehousing unit; and an image sensor positioned at the image side of theoptical imaging lens.